/* ----------------------------------------------------------------------
* Copyright (C) 2010 ARM Limited. All rights reserved.
*
* $Date:        15. February 2012
* $Revision: 	V1.1.0
*
* Project: 	    CMSIS DSP Library
* Title:	    arm_mat_scale_q15.c
*
* Description:	Multiplies a Q15 matrix by a scalar.
*
* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
*
* Version 1.1.0 2012/02/15
*    Updated with more optimizations, bug fixes and minor API changes.
*
* Version 1.0.10 2011/7/15
*    Big Endian support added and Merged M0 and M3/M4 Source code.
*
* Version 1.0.3 2010/11/29
*    Re-organized the CMSIS folders and updated documentation.
*
* Version 1.0.2 2010/11/11
*    Documentation updated.
*
* Version 1.0.1 2010/10/05
*    Production release and review comments incorporated.
*
* Version 1.0.0 2010/09/20
*    Production release and review comments incorporated.
*
* Version 0.0.5  2010/04/26
*    incorporated review comments and updated with latest CMSIS layer
*
* Version 0.0.3  2010/03/10
*    Initial version
* -------------------------------------------------------------------- */

#include "arm_math.h"

/**
 * @ingroup groupMatrix
 */

/**
 * @addtogroup MatrixScale
 * @{
 */

/**
 * @brief Q15 matrix scaling.
 * @param[in]       *pSrc points to input matrix
 * @param[in]       scaleFract fractional portion of the scale factor
 * @param[in]       shift number of bits to shift the result by
 * @param[out]      *pDst points to output matrix structure
 * @return     		The function returns either
 * <code>ARM_MATH_SIZE_MISMATCH</code> or <code>ARM_MATH_SUCCESS</code> based on the outcome of size checking.
 *
 * @details
 * <b>Scaling and Overflow Behavior:</b>
 * \par
 * The input data <code>*pSrc</code> and <code>scaleFract</code> are in 1.15 format.
 * These are multiplied to yield a 2.30 intermediate result and this is shifted with saturation to 1.15 format.
 */

arm_status arm_mat_scale_q15(
    const arm_matrix_instance_q15* pSrc,
    q15_t scaleFract,
    int32_t shift,
    arm_matrix_instance_q15* pDst)
{
	q15_t* pIn = pSrc->pData;                      /* input data matrix pointer */
	q15_t* pOut = pDst->pData;                     /* output data matrix pointer */
	uint32_t numSamples;                           /* total number of elements in the matrix */
	int32_t totShift = 15 - shift;                 /* total shift to apply after scaling */
	uint32_t blkCnt;                               /* loop counters */
	arm_status status;                             /* status of matrix scaling     */

#ifndef ARM_MATH_CM0

	q15_t in1, in2, in3, in4;
	q31_t out1, out2, out3, out4;
	q31_t inA1, inA2;

#endif //     #ifndef ARM_MATH_CM0

#ifdef ARM_MATH_MATRIX_CHECK

	/* Check for matrix mismatch */
	if((pSrc->numRows != pDst->numRows) || (pSrc->numCols != pDst->numCols)) {
		/* Set status as ARM_MATH_SIZE_MISMATCH */
		status = ARM_MATH_SIZE_MISMATCH;
	} else
#endif //    #ifdef ARM_MATH_MATRIX_CHECK
	{
		/* Total number of samples in the input matrix */
		numSamples = (uint32_t) pSrc->numRows * pSrc->numCols;

#ifndef ARM_MATH_CM0

		/* Run the below code for Cortex-M4 and Cortex-M3 */
		/* Loop Unrolling */
		blkCnt = numSamples >> 2;

		/* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
		 ** a second loop below computes the remaining 1 to 3 samples. */
		while(blkCnt > 0u) {
			/* C(m,n) = A(m,n) * k */
			/* Scale, saturate and then store the results in the destination buffer. */
			/* Reading 2 inputs from memory */
			inA1 = _SIMD32_OFFSET(pIn);
			inA2 = _SIMD32_OFFSET(pIn + 2);

			/* C = A * scale */
			/* Scale the inputs and then store the 2 results in the destination buffer
			 * in single cycle by packing the outputs */
			out1 = (q31_t)((q15_t)(inA1 >> 16) * scaleFract);
			out2 = (q31_t)((q15_t) inA1 * scaleFract);
			out3 = (q31_t)((q15_t)(inA2 >> 16) * scaleFract);
			out4 = (q31_t)((q15_t) inA2 * scaleFract);

			out1 = out1 >> totShift;
			inA1 = _SIMD32_OFFSET(pIn + 4);
			out2 = out2 >> totShift;
			inA2 = _SIMD32_OFFSET(pIn + 6);
			out3 = out3 >> totShift;
			out4 = out4 >> totShift;

			in1 = (q15_t)(__SSAT(out1, 16));
			in2 = (q15_t)(__SSAT(out2, 16));
			in3 = (q15_t)(__SSAT(out3, 16));
			in4 = (q15_t)(__SSAT(out4, 16));

			_SIMD32_OFFSET(pOut) = __PKHBT(in2, in1, 16);
			_SIMD32_OFFSET(pOut + 2) = __PKHBT(in4, in3, 16);

			/* update pointers to process next sampels */
			pIn += 4u;
			pOut += 4u;


			/* Decrement the numSamples loop counter */
			blkCnt--;
		}

		/* If the numSamples is not a multiple of 4, compute any remaining output samples here.
		 ** No loop unrolling is used. */
		blkCnt = numSamples % 0x4u;

#else

		/* Run the below code for Cortex-M0 */

		/* Initialize blkCnt with number of samples */
		blkCnt = numSamples;

#endif /* #ifndef ARM_MATH_CM0 */

		while(blkCnt > 0u) {
			/* C(m,n) = A(m,n) * k */
			/* Scale, saturate and then store the results in the destination buffer. */
			*pOut++ =
			    (q15_t)(__SSAT(((q31_t)(*pIn++) * scaleFract) >> totShift, 16));

			/* Decrement the numSamples loop counter */
			blkCnt--;
		}

		/* Set status as ARM_MATH_SUCCESS */
		status = ARM_MATH_SUCCESS;
	}

	/* Return to application */
	return (status);
}

/**
 * @} end of MatrixScale group
 */
